In a letter sent to Cervical Screening Wales and seen by GP, Powys GP Dr Chris Nevill argued that testing below this age produces ‘harmful’ false positives.

All women in Wales aged 20-64 are invited for cervical screening every three years. A similar policy exists in Scotland.

But women in England are only invited once they are aged 25 and over.

Dr Nevill wants a full review of the evidence base for screening age and a shift to match England’s policy. ‘It is sobering to find that the consultant evidence-based body of opinion is in agreement that smears from the age of 20-24 are not only a waste of time but dangerous to the young women on whom they are inflicted,’ he wrote.

Speaking to GP, Dr Nevill said: ‘The evidence base is strongly against this practice. We can’t have a preventive programme that actually causes harm.’

He argued that frequent false positives from testing cause significant psychological harm. It also unnecessarily exposes young women to harm caused by treating abnormalities that might otherwise have disappeared by age 25, he claimed.

Many of the practice’s patients have friends who live over the nearby border with England, he added.

Inviting young women for screening when their friends in England are not leaves them confused and anxious, he said, and risks patients losing faith in screening measures.

Dr Nevill also criticised the Welsh government, which was also sent the letter, for failing to track the evidence base. ‘There’s been a lack of revision [of the policy] from the Welsh government. It has been left in the dark,’ he said.

A spokesman for the Welsh government defended the policy: ‘It is important that women attend their screening when invited to do so. Early identification and treatment can improve the outcome for patients. Women should also remain vigilant in-between screening.’

The spokesman added that the government was ‘continually monitoring and evaluating the latest evidence to ensure our screening programmes target the appropriate age group’, including reviewing the starting age of cervical cancer screening.